Float gauge assembly for storage tanks

ABSTRACT

A float gauge assembly for a storage tank having a port with an opening includes a body for attachment to the port of the storage tank and a gauge mountable to the body, the gauge having a gauge face for indicating a level or amount of material present in the storage tank, a float mechanism mounted to the body and cooperating with the gauge, the float mechanism including a float movable relative to the body in an operating position, the float being sized so that the float is unable to be inserted into the storage tank though the opening in the port, and a tube coupled to the float and having a dimension sized for inserting through the opening in the port, and an alignment element configured to rotationally fix the tube to the body when the float is in the operating position so that the gauge face accurately indicates the level of material in the storage tank when mounted to the body.

CROSS-REFERENCE TO RELATED APPLICATION(S)

The present application is a continuation of U.S. Ser. No. 14/207,793, filed Mar. 13, 2014, which claims priority to and the benefit of U.S. Provisional Patent Application Ser. No. 61/782,895, filed Mar. 14, 2013, both of which are hereby incorporated by reference in their entirety.

BACKGROUND OF THE INVENTION

1. Field of the Invention

The present invention relates generally to gauge assemblies and, more particularly to, a float gauge assembly used for storage tanks.

2. Description of the Related Art

Storage tanks for fluids such as liquefied petroleum gas (LPG) and anhydrous ammonia (NH3) commonly have rotary gauges for detecting a level of material stored in the storage tank. Often, these rotary gauges are attached to the storage tanks at small openings into the storage tank such as a 1″ National Pipe Thread (NPT) opening. Lately, there has been a desire to replace such rotary gauges with float gauges. However, in order to replace the rotary gauge with a float gauge, the float gauge must also fit into the same small opening. Therefore, there is a need in the art for a float gauge that is capable of fitting to storage tanks with small openings.

SUMMARY OF THE INVENTION

Accordingly, the present invention provides a float gauge assembly for a storage tank having a port with an opening. The float gauge assembly includes a body for attachment to the port of the storage tank and a gauge mountable to the body. The gauge has a gauge face for indicating a level or amount of material present in the storage tank. The float gauge assembly also includes a float mechanism mounted to the body and cooperating with the gauge. The float mechanism includes a float movable relative to the body in an operating position, the float being sized so that the float is unable to be inserted into the storage tank though the opening in the port, and a tube coupled to the float and having a dimension sized for inserting through the opening in the port. The float gauge assembly further includes an alignment element configured to rotationally fix the tube to the body when the float is in the operating position so that the gauge face accurately indicates the level or amount of material in the storage tank when mounted to the body.

One advantage of the present invention is that a new float gauge assembly is provided for a storage tank. Another advantage of the present invention is that the float gauge assembly may be used to replace a rotary gauge. Yet another advantage of the present invention is that the float gauge assembly is capable of fitting to storage tanks with small openings. Still another advantage of the present invention is that the float gauge assembly includes an alignment element configured to rotationally fix the assembly to the opening when a float is in the operating position so that a gauge face accurately indicates a level or amount of material in a storage tank when mounted to the opening.

Other features and advantages of the present invention will be readily appreciated, as the same becomes better understood, after reading the subsequent description taken in conjunction with the accompanying drawings.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a perspective view of one embodiment of a float gauge assembly, according to the present invention, illustrating a float mechanism separated from a gauge assembly.

FIG. 1A is a fragmentary view of the float gauge assembly of FIG. 1, illustrated with positioning of the float gauge assembly in a storage tank with a man-way access A.

FIG. 2 is a partial sectional and exploded view of the float gauge assembly of FIG. 1.

FIG. 2A is a partial exploded view of the float gauge assembly of FIG. 1.

FIG. 3 is a partial sectional view of the float gauge assembly of FIG. 1.

FIG. 4 is a partial sectional view of the float gauge assembly of FIG. 1.

FIG. 5 is a perspective view of a collar of the float gauge assembly of FIG. 1.

FIG. 6 is a front view of the collar of FIG. 5.

DESCRIPTION OF THE PREFERRED EMBODIMENT(S)

Referring to the drawings and in particular FIGS. 1 and 1A, one embodiment of a float gauge assembly 10, according to the present invention, is shown. In the embodiment illustrated in FIG. 1A, the float gauge assembly 10 is attached to a storage tank 12 to detect and indicate a level or amount of material stored in an interior 13 of the storage tank 12, e.g., percent of tank volume from 0 to 100 percent. It should be appreciated that the float gauge assembly 10 can be used with any stored material suitable for float gauges, but is often used for storage tanks containing LPG and NH3.

The storage tank 12 has a man-way access A that allows an installer of the float gauge assembly 10 to enter the interior 13 of the storage tank 12. The storage tank 12 also has an internally threaded port 14 that opens into the interior 13 of the storage tank 12 from outside. The float gauge assembly 10 is attached to the storage tank 12 through the port 14 so that a gauge face 16 of the float gauge assembly 10 can be viewed from outside the storage tank 12 to determine the level of material inside the storage tank 12. In one embodiment, the port 14 has a 1 inch NPT opening. In other embodiments, the port 14 has different sized openings.

Referring to FIGS. 1 through 4, the float gauge assembly 10 includes a flange body, generally indicated at 15, fitted to the port 14. The flange body 15 has a flange 17 with a plurality of circumferentially spaced openings 17 a for fasteners 49 (FIG. 3). In the embodiment illustrated, there are eight (8) equally circumferentially spaced openings 17 a. The flange body 15 also has a neck 19 extending rearward from the flange 17. The neck 19 has a first tubular portion 21 with a first diameter and a second tubular portion 23 with a second diameter greater than the first diameter. The first tubular portion 21 is externally threaded for inserting into the internally threaded port 14. The second tubular portion 23 is externally threaded. The flange body 15 is made of a metal material. The flange body 15 is integral, unitary, and one-piece.

The float gauge assembly 10 also includes a threaded nut 25 having a threaded internal bore 25 a that, when the flange body 15 is threaded into the port 14, is unthreaded relative to the flange body 15 so as to bear against an outer surface 14 a of the port 14. The threaded nut 25 is shown as a wing nut that has a bearing surface 27 that contacts and bears against the outer surface 14 a of the port 14 to further secure the flange body 15 to the port 14. During installation, the flange body 15 is oriented relative to the storage tank 12 so that two of the openings 17 a for fasteners are located at diametrically opposed nine o'clock and three o'clock positions (see FIG. 4). It should be appreciated that the threaded internal bore 25 a threadably engages the threaded second tubular portion 23.

The float gauge assembly 10 also includes a float mechanism, generally indicated at 18, that operates to detect changes in the level or amount of material in the interior 13 of the storage tank 12. The float mechanism 18 includes a float arm 20 and a float 22 is connected to the float arm 20 at a first end. The float arm 20 and float 22 move relative to the flange body 15 when in an operating position. The float mechanism 18 also includes a counterbalance assembly, generally indicated at 24, attached to the float arm 20 at a second end. The float mechanism 18 further includes a drive shaft 26 and a gear box 28 to rotatably drive the drive shaft 26 through the gear box 28 as the float 22 is raised or lowered by the material in the interior 13 of the storage tank 12 as the level of the material in the interior 13 of the storage tank 12 is raised or lowered. The drive shaft 26 extends from the gear box 28 and the gear box 28 is connected to the float arm 20. The float mechanism 20 also includes a tube 30 coaxially surrounding the drive shaft 26. The tube 30 is sized for insertion through the port 14. The tube 30 has a diameter smaller than a diameter of an opening 14 b in the port 14. The drive shaft 26 rotates within the tube 30. It should be appreciated that the float arm 20 pivots about a pivot axis relative to tube 30 when raised or lowered, as is conventional in the art.

In some embodiments, the float 22 is sized such that the float 22 is unable to be inserted into the interior 13 of the storage tank 12 through the opening 14 b of the port 14. The float 22 has a length and a width with the width being larger than a diameter of the opening 14 b through the port 14. As a result, the float mechanism 18 must be first inserted into the interior 13 of the storage tank 12 through the man-way access A.

The tube 30 has a connector 32 opposite the gear box 28 and integrally formed with the rest of the tube 30. The connector 32 defines a central bore 32 a through which the drive shaft 26 extends to protrude forward from the connector 32. The connector 32 has a threaded outer surface 32 b. During assembly, the installer enters the interior 13 of the storage tank 12 through the man-way access A. The installer then inserts the connector 32 (and additional portions of tube 30) through a central throughbore 33 of the flange body 15—the flange body 15 already being attached to the port 14. The connector 32 is inserted through the central throughbore 33 so that the connector 32 protrudes into a threaded pocket 29 defined in the flange body 15.

Referring to FIGS. 2 through 6, the float gauge assembly 10 includes a collar, generally indicated at 34, having a frustoconical outer surface 34 a and a threaded internal bore 34 b threaded onto the threaded outer surface 32 b of the connector 32. The collar 34 is sized so that, once threaded to the connector 32, the connector 32 is unable to slide back through the central throughbore 33 in the flange body 15. Once the collar 34 is secured to the connector 32, the installer is no longer needed inside the interior 13 of the storage tank 12 and the remaining installation can occur outside of the storage tank 12.

The float gauge assembly 10 also includes a key 35 and the connector 32 and collar 34 have opposing keyways 37, 39 a for receiving the key 35 to rotationally lock the collar 34 to the connector 32. The key 35 and keyways 37, 39 a are generally rectangular in shape, but may have any suitable shape. The keyways 37, 39 a extend axially along the threaded internal bore 34 b. The keyway 37 for the connector 32 is located at the twelve o'clock position circumferentially about the connector 32 when the float mechanism 18 is in an optimal operating position, e.g., freely hanging downwardly under the force of gravity in an empty storage tank 12. Once the collar 34 has been substantially threaded onto the connector 32, and the keyways 37, 39 a aligned, the key 35 is inserted into the keyways 37, 39 a to rotationally lock the collar 34 to the connector 32.

The collar 34 has a rear surface 34 c and at least one, preferably a pair of alignment elements that protrude rearwardly from the rear surface 34 c. In the embodiment illustrated, the alignment elements are pins 36 that are diametrically opposed to one another. The pins 36 are generally cylindrical in shape, but may have any suitable shape. When the collar 34 is keyed to the connector 32, and the float mechanism 18 is in an operating position, the pins 36 are located at nine o'clock and three o'clock positions on the collar 34. It should be appreciated that the pins 36 may be integral, unitary, and one-piece with the collar 34.

During assembly, after the collar 34 is attached to the connector 32 and keyed together, the float mechanism 18 is allowed to hang down under the force of gravity to assume its optimal operating position. This rotationally orients the collar 34/connector 32 relative to the flange body 15 so that the pins 36 are located at nine o'clock and three o'clock positions (see FIG. 4). When the float mechanism 18 has settled into its optimal operating position while hanging down under the force of gravity, the position of the pins 36 is ascertained relative to a plurality of matingly shaped and sized bores 38 defined in a shoulder surface 39 of the flange body 15 opposite the pins 36. There are preferably eight (8) bores 38 that correspond in clock position to the eight openings 17 a in the flange 17. Two of the bores 38 are oriented in the nine o'clock and three o'clock positions if the flange openings 17 a were properly oriented. The pins 36 are then selectively inserted into two of the bores 38 that most closely match the rotational position of the pins 36 when the float mechanism 18 is in its optimal operating position—which in a desired installation will be the two bores 38 at the nine o'clock and three o'clock positions. This will ultimately align the gauge face 16 properly with respect to the float mechanism 18. It should be understood that the float mechanism 18 is operational in other operating positions other than its optimal operating position and deviations from the optimal operating position are within the scope of this invention.

The float gauge assembly 10 also includes a retainer, generally indicated at 40, to retain the collar 34 in position to the flange body 15. The retainer 40 has an inner frustoconical surface 40 a for frictional sliding against the corresponding surface 34 a of the collar 34 and an externally threaded outer surface 40 b. Once the pins 36 are in mating engagement with the flange body 15 via the bores 38, the retainer 40 is threaded into position over the collar 34. As the retainer 40, which is externally threaded, is threaded into the internally threaded pocket 29 of the flange body 15, the frustoconical inner surface 40 a bears against the frustoconical outer surface 34 a of the collar 34 to retain the collar 34 in position.

The float gauge assembly 10 further includes at least one, preferably a pair of fasteners. In one embodiment, the pair of fasteners is a pair of set screws 41 inserted into threaded bores 40 c in the retainer 40. The set screws 41 are inserted after the retainer 40 is threaded into the internally threaded pocket 29 of the flange body 15. The set screws 41 further lock the retainer 40 in position by bearing against the shoulder surface 39 that defines a bottom of the internally threaded pocket 29 of the flange body 15.

The tube 30 is rigidly fixed to the flange body 15 to improve durability and accuracy. In particular, referring to FIGS. 5 and 6, the collar 34 has a collet-style flexible cross section (e.g., broken ring) that is compressed by the frustoconical mating surfaces 34 a and 40 a of the collar 34 and retainer 40, respectively. It should be appreciated that this compression eliminates all clearance between the connecting threads of the collar 34 and the connector 32, thereby rigidly fixing tube 30 to the flange body 15.

The float gauge assembly 10 also includes a hub 44 fixed to an end of the drive shaft 26 opposite the gear box 28 and a magnet 46 fixed to the hub 44 to rotate with the drive shaft 26 as the drive shaft 26 is rotated by the float mechanism 18. The float gauge assembly 10 includes a second flange body, generally indicated at 48 (see FIG. 3), fastened to the flange body 15 by fasteners 49 (e.g., nuts N and threaded shafts T). The second flange body 48 includes a cavity 49 for receiving the magnet 46 fixed to the hub 44. The float gauge assembly 10 also includes a sealing member, e.g., a gasket G, disposed between the flange bodies 15, 48 to seal against leaks between the flange bodies 15, 48.

The float gauge assembly 10 further includes a gauge assembly, generally indicated at 50, mounted to the second flange body 48. The gauge assembly 50 includes a gauge housing 52 and the gauge face 16 disposed in the gauge housing 52. The gauge assembly 50 also includes a second magnet 54 disposed in the gauge housing 52 and a hub 55 that rotates about a pivot pin 56. The second magnet 54 is fixed to the hub 55. The second magnet 54 is aligned with the first magnet 46 so that rotation of the first magnet 46 results in like rotation of the second magnet 54. Thus, when the first magnet 46 rotates upon being driven by the float mechanism 18, the second magnet 54 similarly rotates. The gauge assembly 50 further includes a needle 58 fixed to the hub 55 to indicate on the gauge face 16 the level of material in the storage tank 12. Examples of suitable gauge assemblies are shown in U.S. Design Pat. Nos. D671,022 to Hoffman et al. and D666,933 to Hoffman et al., both of which are hereby incorporated by reference. It should be appreciated that the alignment elements, e.g., pins 36, act to properly align the float mechanism 18 with the gauge assembly 50 so that readings of the liquid level in the interior 13 of the storage tank 12 are accurate.

Embodiments of the present invention have been described in an illustrative manner. It is to be understood that the terminology, which has been used, is intended to be in the nature of words of description rather than of limitation.

Many modifications and variations of the present invention are possible in light of the above teachings. Therefore, the present invention may be practiced other than as specifically described. 

What is claimed is:
 1. A method of installing a float gauge assembly in a storage tank having a port with an opening, said method comprising the steps of: attaching a body having at least one bore to the port of the storage tank; mounting a gauge to the body, the gauge having a gauge face for indicating a level of material present in the storage tank; placing a float mechanism through the port of the storage tank and mounting the float mechanism to the body to cooperate with the gauge, the float mechanism including a float movable relative to the body in an operating position and a tube coupled to the float and having a dimension sized for inserting through the opening in the port; inserting a connector of the tube through the at least one bore of the body, the connector having a first keyway; attaching a collar to the connector, the collar having a second keyway; aligning the first keyway and the second keyway with each other; inserting a key into the aligned first keyway and second keyway to rotationally lock the collar to the connector; and receiving in the at least one bore at least one alignment element protruding from the collar and fixing rotationally the tube to the body when the float is in the operating position so that the gauge face accurately indicates the level of material in the storage tank when mounted to the body.
 2. A method as set forth in claim 1 including the step of receiving the tube extending axially through the at least one bore in the body having a threaded pocket at one end of the at least one bore.
 3. A method as set forth in claim 2 including the step of disposing the connector at one end in the threaded pocket and having a threaded outer surface.
 4. A method as set forth in claim 3 including the step of threadably engaging the collar on the threaded outer surface of the connector.
 5. A method as set forth in claim 4 including the step of protruding the at least one alignment element rearwardly from a rear surface of the collar.
 6. A method as set forth in claim 1 including the step of providing the collar with a frustoconical outer surface.
 7. A method as set forth in claim 6 including the step of disposing a retainer in position over the collar to retain the collar in position to the body.
 8. A method as set forth in claim 7 including the step of providing the retainer with a frustoconical inner surface for frictional sliding against the outer surface of the collar.
 9. A method as set forth in claim 8 including the step of threading the retainer into a threaded pocket of the body and bearing the inner surface against the outer surface of the collar to retain the collar in position.
 10. A method as set forth in claim 9 including the step of providing the collar with a collet-style flexible cross section that is compressed by the mating outer surface and inner surface of the collar and retainer, respectively.
 11. A method as set forth in claim 7 including the step of providing a pair of set screws and inserting the pair of set screws into threaded bores in the retainer after the retainer is threaded into a threaded pocket of the body.
 12. A method as set forth in claim 11 including the step of locking the retainer in position with the pair of set screws by bearing against a shoulder surface that defines a bottom of a threaded pocket of the body.
 13. A method of installing a float gauge assembly in a storage tank having a port with an opening, said method comprising the steps of: attaching a body to the port of the storage tank, the body having a throughbore extending therethrough and a threaded pocket at one end of the throughbore; mounting a gauge to the body, the gauge having a gauge face for indicating a level of material present in the storage tank; mounting a float mechanism to the body to cooperate with the gauge, the float mechanism including a float movable relative to the body in an operating position, the float being sized so that the float is unable to be inserted into the storage tank though the opening in the port and a tube coupled to the float and having a dimension sized for inserting through the opening in the port; and fixing rotationally a pair of pins to the body when the float is in the operating position so that the gauge face accurately indicates the level of material in the storage tank when mounted to the body.
 14. A method as set forth in claim 13 including the step of receiving the pair of pins in a plurality of bores defined in the body.
 15. A method as set forth in claim 14 including the step of selectively inserting the pair of pins into two of the plurality of bores that most closely match a rotational position of the pair of pins when the float mechanism is hanging down under a force of gravity.
 16. A method as set forth in claim 15 including the steps of providing a connector and a collar with opposing keyways, inserting a key into the keyways and locking rotationally the collar to the connector.
 17. A method as set forth in claim 16 including the step of threading a retainer into the pocket over the collar once the pair of pins are disposed in mating engagement with the plurality of bores in the body.
 18. A method as set forth in claim 17 including the step of threadably engaging a pair of fasteners into the retainer to lock the retainer in position.
 19. A method as set forth in claim 13 including the step of connecting a float arm to the float and a gear box to the float arm.
 20. A method as set forth in claim 19 including the step of fixing a hub to an end of a rotatable drive shaft through the gear box and a magnet to the hub to rotate with the drive shaft and cooperate with the gauge and rotatably driving the drive shaft within the tube as the float is raised or lowered by the material in the storage tank as the level of the material in the storage tank is raised or lowered. 